1. Scope of the Invention
The present invention relates to completely amorphous oxide or oxide composite coatings as well as to a process for producing them, especially by using thermal spraying. The invention also relates to a substrate equipped with said coating.
2. Description of the Prior Art
Among the known solutions which are developed to protect surfaces, there are completely amorphous metal coatings and partly crystalline (partly amorphous) and completely crystalline oxide coatings.
U.S. publication 2004/0253381 describes the formation of such a partly crystalline metallic glass coating by heating an already finished metallic coating. The publications WO 2008/049065, WO 2008/049069 and WO 2010/005745, in turn, describe the generation of metal coatings by using processes which utilize heating, whereby the coatings can also become amorphous, depending on the process used.
The properties of the coatings belonging to these known groups differ clearly from the properties of the coatings of the present invention, and also from their manufacturing processes. Even a small fraction of crystalline material significantly changes the properties of a coating. However, in the processes used in the prior art, the crystallizing temperatures and the melting of the components are utilized in such a way that a completely amorphous coating is impossible to achieve. The aim in these has been to achieve only small changes in the crystallization degree, and thus small changes in the properties of the coatings.
Now it has been surprisingly discovered that by using simple processes it is possible to achieve completely amorphous coatings which also utilize the useful properties of the oxides.